Laser moire deflectometry applicable for mini/micro-scale flow visualization

Abstract

In this paper a Laser Moire deflectometry applicable for mini/micro-scale flow visualization is proposed. Based on the moire effect, the displacements of moire fringes can be used to calculate the deflection angle of laser beam, which is induced by the variation of refractive index in thermal flow fluid. Thus, density and temperature distribution of flow fluid can be obtained. The physical and mathematical model of the laser moire deflectometry is presented in detail. A digital image processing method of moire fringes by using Fourier transform is discussed. The researches show that laser moire deflectometry can meet needs of mini/micro-scale flow visualization for measurement sensitivity and high spatial resolution. The measurement of mini/micro-scale temperature field for natural convection of a heated thin wire is experimentally demonstrated by means of the laser moire deflectometry.